Bathrooms and toilets include surfaces where microbes are deposited and proliferate. These surfaces are continually exposed to additional microbes each time a user enters the bathroom, especially if the user uses the toilet. Consequently, it is impractical to effectively disinfect bathroom and toilet surfaces at a rate which provides a disinfected area for each new user.
While it is important to periodically disinfect a toilet, in some circumstances, it is desirable to delay killing microbes which may be present in a user's excrement. For example, the toilet may be a medical toilet which collects and analyzes the user's urine or feces to provide information that is relevant to the user's health status. In another example, the user's excrement may be transferred to an anaerobic digester to produce biofuel or used as fertilizer. Consequently, control of disinfection of surfaces in the bathroom and on the toilet with regard to time and space are needed.
Titanium dioxide composites subjected to ultraviolet light excitation have been shown to possess effective antimicrobial activity. These composites are effective in eliciting the death of both Gram-positive and Gram-negative bacteria. More recently, doped titanium dioxide composites have been found to be activated by visible light and also to possess antimicrobial activity. The properties of these different titanium dioxide composites and their exposure to light of different wavelengths may be useful to design a toilet or full bathroom that includes antimicrobial surfaces.